Initially, each patient will be assessed using the Borg scale to determine the number of strengthening exercise repetitions that patient can carry out. Assessment will be repeated weekly, before the number of repetition is progressed. For stretching exercise, 5 repeat ions will be done each session, in addition patients will be asked to repeat the exercise as a home program exercise. Exercise will be given 3 times weekly, at the University of Benha outpatient clinic, for a period of 3-5 cm of distraction (approximately 8 weeks) or the end of distraction whatever is earlier Exercise for group (A) Knee flexion exercise Patient in supine and gently bend his knee, with keeping the heel in contact with the bed. Bring the heel towards bottom as far as is comfortable .Exercise will be repeated as determined by patient's ability.